1. Field of the Invention
The present invention relates to a booster, especially relates to a booster used to a transportation machine such as an automobile and the like.
2. Description of the Related Art
For instance, a vacuum booster is structured in a manner that two rooms isolated by a power piston, and a power diaphragm are communicated to a negative pressure source such as an intake manifold of an engine, a vacuum pump, and so on, and the two rooms are kept in a negative pressure in a non-operational state. An atmospheric pressure is introduced into one room by actuating an inputting member through operation of a brake pedal and the like, so that the power piston is actuated by a pressure difference of both rooms. A power of the inputting member is boosted by a force generated in the power piston to output to an outputting member. Then, this output force is transmitted to a brake master cylinder or the like.
As described above, the conventional vacuum booster device requires a negative pressure source disposed completely different from a transmission channel for the power of the inputting member as a mechanism to boost, in addition to a force transmitted to the outputting member by the power of the inputting member operated with an operation member such as a brake pedal or the like. That is, the conventional vacuum booster requires a negative pressure source worked by a separate driving force different from a force to drive an inputting member. As a booster, a hydraulic booster, and a pneumatic booster as well as a vacuum booster can be cited. In the case of a hydraulic booster, a hydraulic pump and so on is necessary to be operated by an independent driving force as a source of generating a force to be amplified. Furthermore, in the case of the pneumatic booster, a compressor, a vacuum tank or the like for supplying compressed air is required additionally.